Load indicating spring caster

ABSTRACT

A spring-loaded caster with an indicator to indicate the load applied to the caster.

FIELD OF THE INVENTION

This invention relates to spring-loaded casters and, more particularly,to lever action casters with shock absorbing springs.

BACKGROUND OF THE INVENTION

Mechanisms are known to mount wheels as, for example, via casters andwith the wheel being secured in a manner that with increased loading thesupport for the wheel becomes deflected as by the deflection of aspring.

Previously known devices suffer the disadvantage that it is difficult toknow whether a spring-loaded caster is being subjected to loads whichexceed preferred operational limits for the spring.

Previously known devices also suffer the disadvantage that relativelycomplex structures are required for mounting of a wheel to a support soas to permit the wheel to be supported in a spring biased manner.

SUMMARY OF THE INVENTION

To at least partially overcome the disadvantages of the previously knowndevices, the present invention provides a caster carrying a gauge bywhich the load carried by the caster is displayed visible to a user. Theinvention is directed to provide an indicating system such that thecaster can be visually inspected to determine the load which it isbearing and to see if it is within preferred limits.

To overcome disadvantages of the previously known devices, the presentinvention also provides a simplified construction for a wheel mount inwhich the supporting structure itself deflects under loads.

An object of the present invention is to provide in a spring-loadedcaster, an indicating system such that the caster can be visuallyinspected to see the load which it is bearing.

Another object is to provide a simplified support for mounting a wheelin which the support structure itself deflects under load.

Another object is to provide a simplified construction for aspring-loaded caster in which a support for the wheel comprises aunitary element.

The invention provides a spring-loaded caster with an indicator toindicate the load applied to the caster. The spring-loaded caster has awheel mounted to a lever which pivots relative a support against thebias of a spring when loads are applied. The indicator preferably has afirst indicator component on the lever and a second indicator componenton the support. The two indicator components are located adjacent eachother so that their relative positions indicate loading on the casterand can be easily seen by the human eye while the caster is in use.

Swiveling casters typically swivel about a substantially vertical swivelaxis. The caster has a wheel which is journalled for rotation about ahorizontal wheel axis. The wheel axis is typically horizontally spacedfrom an extension of the swivel axis and this spacing or offsetfrequently is a significant factor in determining safe loads which canbe carried without failure. The present invention is particularlyadvantageous with swiveling casters where wheel axis are offset from theswivel axis. In providing a load indicating system, a method is providedpreferably sensed visually by which loads can be kept in a safe range.Sensing, of course, could also be via electronic or other automaticindication and sensing devices than merely visual inspection orindication.

The invention also provides a novel construction for a wheel mountassembly in which a resilient member can serve to couple the wheelsupporting lever to a support for deflection to provide relativemovement of the lever and support under varying loads. The resilientmember can serve as a primary biasing device which resists relativemovement of the lever and support or can be complemented by anadditional spring.

In one aspect, the present invention provides a caster assemblycomprising a mounting member mountable to an article,

a support member mounted to the mounting member for swiveling about asupport axis,

an elongate lever pivotably coupled to the support member for pivotingof the lever relative the support member about a pivot axis generallynormal to the support axis,

a wheel rotatably mounted to the lever for rotation about a wheel axisspaced from the pivot axis and parallel the pivot axis;

a spring member disposed between the lever and the support member suchthat pivoting of the lever relative the support member about the pivotaxis at least in one direction deflects the spring member,

a support indicator carried by the support member spaced from the pivotaxis radially relative the pivot axis,

a lever indicator carried by the lever spaced from the pivot axisradially relative the pivot axis,

the support indicator and lever indicator disposed in juxtapositionedcomplementary relation to move relative each other on pivoting of thelever relative the support member about the pivot axis and provide avisual indication of the extent of deflection of the spring member.

In another aspect, the present invention provides a wheel supportassembly comprising a support member adapted to be coupled to anarticle,

an elongate lever member having a first end and a second end,

a first spring member coupling the first end of the lever member to thesupport member,

a wheel rotatably mounted to the second end of the lever member forrotation about a wheel axis spaced from the first spring member,

the first spring member comprising a resilient member which ondeflection under loads applied to the wheel assembly moves the secondend of the lever member carrying the wheel relatively closer to orfarther away from the support member between extended and retractedpositions while maintaining the wheel axis in all different positionsbetween the extended and retracted positions parallel the orientation ofthe wheel axis in the extended position.

In another aspect, the present invention provides a wheel assemblycomprising:

an elongate generally U-shaped flex member having a first leg and asecond leg joined by a bridging bight,

the first leg comprising a support portion adapted to be secured to anarticle,

the second leg having a wheel rotatably mounted thereto for rotationabout a wheel axis,

the bight comprising a resilient first spring member which resilientlydeflects under loads applied between the support portion and the wheelto move the wheel relatively closer to or farther away from the supportportion between respective retracted and extended positions,

the flex member maintaining the wheel axis in all different positionsbetween the retracted position and the extended position parallel anorientation of the wheel axis in the extended position.

In another aspect, the present invention provides a wheel supportassembly comprising:

a support member adapted to be coupled to an article,

a spring member having a first end and a second end,

an lever member having a first end and a second end,

a wheel rotatably mounted to the second end of the lever for rotationabout a wheel axis,

the first end of the spring member fixedly secured to the support memberand the first end of the lever member fixedly secured to the second endof the spring member, whereby the spring member and lever membertogether comprise a continuous appendage extending from the supportmember and supporting the wheel at a distal end,

the spring member deflecting under loads applied between the supportmember and the wheel to move the wheel relatively closer to the supportmember under increasing loads.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects and advantages of the present invention will becomeapparent from the following description taken together with theaccompanying drawings in which:

FIG. 1 is a pictorial view of a caster in accordance with a firstembodiment of the present invention with a brake in a locked position;

FIG. 2 is a side view of the caster of FIG. 1 in a retracted positionshowing the brake in an unlocked position in solid lines and in a lockedposition in dotted lines;

FIG. 3 is an end view of FIG. 2 with the brake in a locked position;

FIG. 4 is a top view of the caster of FIG. 2 with the brake in anunlocked position;

FIG. 5 is a partial cross-sectional view along line V-V′ of FIG. 4;

FIG. 6 is a cross-sectional view along section line VI-VI′ of FIG. 5;

FIG. 7 is a side view of the caster of FIG. 1 the same as in FIG. 2 butwith the caster in an extended position;

FIG. 8 is a pictorial view of a second embodiment of a caster inaccordance with the present invention;

FIG. 9 is a side view of the caster shown in FIG. 8;

FIG. 10 is a top view of the caster shown in FIG. 9;

FIG. 11 is a partial cross-sectional side view of the caster of FIG. 10along line X-X′;

FIG. 12 is a side view similar to that of FIGS. 9 and 11, however,showing the caster in a fully compressed position;

FIG. 13 is a schematic plan view of a metal sheet from which a unitaryflex element of the caster of FIG. 8 may be formed;

FIG. 14 is a schematic partially cross-sectional side view of a thirdembodiment of a caster in accordance with the present invention in anuncompressed position; and

FIG. 15 is a view of the caster as in FIG. 14, however, in a compressedposition.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 7 illustrate a caster 10 in accordance with a firstembodiment of the present invention.

Caster 10 has a mounting member 12 comprising a plate with holes forattachment by bolts or the like as to the bottom of, for example, autility cart.

Mounting member 12 is coupled to a support member 14 for relativeswiveling about a swivel axis 16. The swivel coupling between themounting member 12 and support member 14 may be of any known type. Aswivel coupling 15 is shown with two races of ball bearings 18 and 20and an intermediate cup 22 and a lower disc 24 secured together by abolt 24 coaxial with swivel axis 16.

Support member 14 includes the intermediate cup 22 from which twospaced, mirror-image legs 26 extend downwardly to their distal ends 28.The support member 14 includes a spring housing 40 secured to the legs26.

A lever mechanism 30 has two mirror-image, spaced lever arms 32. Eachlever arm 32 is coupled to a respective leg 26 of the support member 14near the lower distal end 28 of the leg for pivoting about a pivot axis34.

A wheel 36 is rotatably mounted on a wheel axle 37 between the two leverarms 32 at a rearward first end 39 of the lever arms for journalledrotation about a wheel axis 38 parallel the pivot axis 34.

The spring housing 40 is of a U-shape as seen in top, plan view in FIG.4 having two mirror image side members 42 joined by a bight member 44 atthe forward edges of the side members. The side members 42 have rearedges which are fixedly secured to forward edges 50 of the legs 26 sothat the spring housing 40 is supported in a cantilevered manner forwardof the legs 26. As seen in FIGS. 5 and 6, the spring housing 40 has abase member 52 extending between the side members 42 near their bottomedges and fixedly secured to the side members 42 and bight member 44.

Lever arms 32 extend rearwardly of the legs 26 of the support member tounderlie the spring housing 40 and carry at forward, second ends 56 ofthe lever arms a pivot bolt 58 extending between the arms 32 parallelthe pivot axis 34. An anchor bolt 60 has an eyelet 62 at a lower endengaged about pivot bolt 58 and extends upwardly between the lever arms32 through an opening 64 in base member 52 and into the interior ofspring housing 40.

The uppermost end of anchor bolt 60 is threaded and carries a threadednut 63 which engages a washer 65. A coil spring 66 is captured on theanchor bolt 60 between the washer 65 and base member 52 such that thespring 66 biases the lever mechanism 30 to draw the forward, second ends56 of the lever arms 32 upwardly into engagement with the spring housing40. In this regard, upper surfaces of the lever arms 32 and lowersurfaces of the side members 42 serve to engage and provide a stopmechanism limiting rotation of the lever mechanism counterclockwise in aretracted position as seen in FIG. 5.

Each side member 42 of the support member 14 is provided with anindicator window 68 through which the washer 65 is visible.

Indicator markings 70 are provided adjacent the indicator window 68 asvertically spaced lines which assist a person viewing the caster todetermine the relative location of the washer 65. Preferably, the linesrepresent quantified values of the loading to which the caster 10 issubjected.

By selection of an appropriate strength. spring 66 and by compression ofthe spring 66 to a desired amount by nut 63, the forces required movethe washer 65 relative the indicator window can be quantified and thelines located to indicate actual loadings experienced by the caster 10,for example, in pounds or kilograms. Providing quantitative indicationsof loading is not necessary and merely having the indicator window 68 topermit viewing of the washer 65 at some positions can indicate, forexample, whether loading may exceed desired maximums or be within adesired range.

FIG. 2 shows the caster in a retracted position as may arise with noload or only a small load applied to the caster as indicated by theindicator washer 65 indicating a load of approximately 0 pounds. FIG. 7shows the caster in an extended position when a substantial load hasbeen applied. In FIG. 7, the indicator washer indicates a load ofgreater than 400 pounds. As seen in FIGS. 2 and 7, the lever arms 32carry a stop protrusion 69 which engages the left-hand edge of the legs32 and provide a stop mechanism limiting rotation of the lever mechanismclockwise in a fully extended position as seen in FIG. 7. Preferably, inuse, the caster will not be used under loads in which the caster is inthe fully extended position. A user can, of course, determine the loadby visual inspection of the window 68.

FIGS. 1 to 6 also show a known brake mechanism 70 carried on the rearfirst end 39 of the lever arms and manually activatable between anunlocked position shown in solid lines in FIGS. 2 and 5 and in a lockedposition shown in dashed lines in FIGS. 2 and 5. In a locked position,the brake mechanism 70 prevents rotation of the wheel 36 about wheelaxis 38.

The spring-loaded caster 10 shown in FIGS. 1 to 7 is merely one form ofa spring caster. Many other forms and arrangements of spring casters areknown including those in which the wheel is mounted for rotation about awheel axis and supported to a load bearing member by a spring such thatload applied deflects the spring and changes the relative location ofthe wheel relative its mounting. The springs may be compressed in avertical direction as shown in FIGS. 1 to 6, or adapted to be compressedhorizontally or at angles thereto taught by known spring-loaded casters.The indicator mechanism may be similarly oriented. Other forms ofspring-loaded casters to which an indicator mechanism in accordance withthe present invention is applicable include those taught by thefollowing U.S. patents whose teachings are incorporated herein byreference:

U.S. Pat. No. 5,40,469 to Simonsen issued Mar. 28, 1995

U.S. Pat. No. 5,347,680 to Rippe issued Sep. 20, 1997

U.S. Pat. No. 3,041,656 to Goodall issued May 31, 1960

U.S. Pat. No. 4,534,433 to Burbank issued Aug. 13, 1985

U.S. Pat. No. 5,581,843 to Purnell issued Dec. 10, 1996

U.S. Pat. No. 2,942,290 to Segal issued May 14, 1957

U.S. Pat. No. 2,227,875 to Boden issued Jul. 8, 1938

U.S. Pat. No. 2,707,795 to Skupas issued May 10, 1955.

The embodiment of FIGS. 1 to 7 shows indicator windows 68 in sidemembers 42. A similar indicator window could be provided in bight member44. The indicator window could be provided on the lever mechanism 30 andan indicator pointer on the support member.

The indicator mechanism shown in FIGS. 1 to 7 is but one arrangement tovisually illustrate the extent to which the spring is deflected. Manyother arrangements may be provided preferably with a first indicatorcarried on the lever mechanism 30 and a second indicator carried on thesupport member 14, with the first and second indicators in juxtaposedcooperating relation to indicate relative positions.

For example, the washer could have a pointer extending therefrom to moredirectly point to an indicator on the support member. The washer couldhave at its outer periphery an axially extending flange painteddifferent colors as, for example, green or red at different axiallocations so that the color green or red would appear in a smallerwindow in the side members depending on the extent of compression of thespring and, therefore, relative movement of the washer.

The indicator mechanism is shown forward of the support legs but couldbe provided rearward thereof.

Many different forms and configurations of springs may be used includingcoil springs, disc springs, leaf springs, gas cylinders and the like.Compound spring arrangements may be used. The springs may compriseresilient metal or other materials such as resilient elastomericmaterials, for example, compressible discs of rubber. The springs may bedeflected under loading either to be compressed or expanded. Where thewheel is carried on an elongate lever, the wheel may be pivotablycoupled to the lever at any point along the length of the lever spacedalong the longitudinal of the lever from the point about which the leverpivots.

In the caster of FIGS. 1 to 7, the support member 14 and lever mechanism30 are separate elements which are joined together at each side by twoshort bolt and nut connectors 72, one on each side joining a lever arm32 with a respective leg 26 of the support member 14 so as to have thelever mechanism pivot about the pivot axis 34 journalled on thecoaxially aligned bolt and nut connectors 72.

Reference is made to FIGS. 8 to 13 which show a second embodiment of acaster 10 in accordance with the present invention and in which the samereference numerals are used as in FIGS. 1 to 7 to show similar elements.

The caster 10 of FIGS. 8 to 12 is different from the caster of FIGS. 1to 7, notably, in that the support member 14 and lever mechanism 30 areformed as a unitary flex element generally indicated as 74, preferably,consisting of one piece of sheet metal formed into a generally U-shapeas by stamping and drawing. Alternately, support member 14 could beformed from plastic as by injection molding.

The flex member 74 is to be best understood as having three portions ofwhich a first end portion is the support member 14 and a second endportion is the lever mechanism 30. A third portion is a resilient bridge76 which is in between the support member 14. and lever mechanism 30joining the support member 14 to the lever mechanism 30.

FIG. 13 schematically shows a plan view of a flat sheet 73 of metal fromwhich the flex element 74 is to be formed by stamping and bending. Thesheet 73 is symmetrical about a longitudinally extending center line120.

The bridge 76 is indicated as comprising that portion between the dashedlines 78 and 80. At a first end of the bridge 76 at line 78, the bridge76 joins an end of the support member 14. At a second end of the bridge76 at line 80, the bridge 76 joins an end of the lever mechanism 30. Thesupport member 14 is to be bent along dashed side lines 82 and 84 tohave its legs 26 extend as side flanges along the sides of and normal toits central support panel 86. The lever mechanism 30 is to be bent alongdashed side lines 88 and 90 to have its lever arms 32 extend as sideflanges along the sides of and normal to its central lever panel 92. Thelever arms 32 carry wheel axle openings 94 so that the wheel axle mayextend therebetween.

The flat sheet 73 is bent to form the flex element 74 as a U-shapedmember as seen in FIG. 8.

On the U-shaped flex element 74, the center line 120 also assumes aU-shape and the center line lies in a flat plane indicated as sectionline X—X′ in FIG. 10 when the flex element is in the extended position.The flex element 74 is configured so that in the flex element 74deflecting to move between the extended and retracted positions, thecenter line is maintained substantially in such flat plane. Suchcontrolled deflection of the flex member 74 may be accomplished to alarge measure by the configuration of the bridge 76 joining the supportmember 14 and lever mechanism 30. However, in addition, lateral guidemembers may be provided on the support member 14 and lever mechanism 30to constrain the support member 14 and lever mechanism 30 duringrelative movement so that the center line 120 is maintained in the flatplane.

With the support member 14 and the lever mechanism 30 suitably formed,stamped and/or bent to have the desired three-dimensional shape shown,the metal sheet 73 is bent so as to form the bridge 76 into a generallyU or C-shape as best shown in FIG. 8 and with the support legs 26 andcentral support panel 86 to form an elongate channelway to rest inside achannelway formed by the lever arms 32 and central lever panel 52extending parallel each other with outside surface 98 of each supportleg 26 in close interfacing relation with inside surfaces 100 of theadjacent lever arm 32.

The channelway formed by the lever arms 32 and central lever portion 52extends longitudinally parallel the center line 120 and opens towardsthe support member 14 to receive the support member 14 therein in theextended position with the support member 14 to move farther into thechannelway of the lever mechanism 30 in moving toward the retractedposition. The outside lateral surfaces 98 of each support leg 26 are inclose interfacing relation with the inside lateral surfaces 100 of eachlever arm 32 for engagement to constrain each during relative movementbetween the extended and retracted position to maintain the center linein alignment in the flat plane. Each lever arm 32 carries an elongateslot 102 to receive a limit pin 104 which extends through the pinopening 106 in the adjacent support leg 26. The limit pin 104 has anelongate central cylindrical portion 103 and an enlarged cylindricalhead 105 at each end. The limit pin 104 extends across the full width ofthe caster as shown in dashed lines in FIG. 10, with its enlarged heads105 disposed laterally outside the lever arms 32. The pin 104 and itsheads 105, which are sized to be larger than the width of the slots 102assist in preventing the lever arms 32 from spreading apart away fromeach other as could give rise to failure under excessive loading. Themovement of the limit pins 104 in their respective elongate slots 102 inthe lever arms 32 limits the extent to which the support member 14 andlever mechanism 30 may be deflected towards and away from each other bydeflection of the flex element 74 over the resilient bridge 76.

The engagement of the limit pin 104 with the upper ends of the slots 102provides a compression stop mechanism assisting in preventing furthercompression of the flex member. Similarly, the engagement of the limitpin 104 with the lower end of the slots 102 provides an expansion stopmechanism assisting in preventing further expansion of the flex member.Various other stop mechanism can be provided as, for example, bosses onlegs 26 to engage the upper edge of legs 32.

The limit pin 104 may be formed by a bolt and nut. The limit pin 104need not extend across the width of the caster and a separate bolt andnut or riveted member could be provided at each side. The head 105 ofthe limit pin 104 also serves as an indicator located proximate linemarkings 70 of an indicator gauge scale. Relative movement of the head105 of the limit pin 104 in the slot 102 serves to indicate the extentof deflection and, therefore, the loading applied.

As best seen in FIGS. 11 and 13, the central support panel 86 has anopening 108 punched therein so as to form a downwardly extendingcircular boss 110. Similarly, the central lever panel 92 has an opening112 punched therein so as to form an upwardly extending circular boss114 which is axially aligned with boss 110. A coil spring 66 has a firstend disposed about boss 110 and a second end disposed about boss 114 soas to retain the spring 66 between the support member 14 and the levermechanism 30 adapted to bias them apart. The coil spring 66 is coaxialabout a spring axis which lies in the flat plane in which the centerline 120 lies. Preferably, in assembly, the spring will have apredetermined size and strength and will be captured between the supportmember 14 and lever mechanism 30 during bending of the bridge 76 intoits U shape. Subsequently, the limit pins 104 may be inserted to retainthe spring 66 in an initial portion with the lever mechanism 30 in anextended position relative the support member 14 as seen in FIGS. 9 and11 with the limit pins 104 engaging the upper end of slots 102. Onapplying loading onto the caster, the load compresses the spring 66 anddeflects the resistant bridge 76 so that the lever mechanism 30 may moverelative the support member 14 to the retracted position as shown inFIG. 12 with the limit pins 104 engaging the lower end of slots 102.

The wheel axle 37 extends from one lever arm 32 to the other to securethe wheel 36 therebetween rotatable about the wheel axis 38. The limitpins 104 extends parallel the axis 38. The deflection of the flexelement 74 about the bridge 76 effectively results in relative pivotingof the support member 12 and the bridging mechanism 30 about animaginary pivot axis which is parallel the wheel axis 38 and located,for example, near to, or forward of, the bridge 76 but, in any event,spaced from the wheel axis 38 radially relative of the wheel axis 38.The bridge 76 provides a living hinge such that deflection of the bridge76 provides for relative movement of the support member 12 and bridgingmember 30 about a rotational or imaginary axis parallel the wheel axis.This imaginary axis is not necessarily fixed relative the flex elementbut may move its relative location depending on load conditions. Indeflection of the flex element 74, the wheel 36 is moved to differentpositions, however, the wheel axis 38 is maintained parallel, that is,the wheel axis 38 of the wheel in any position is parallel to the wheelaxis when the wheel is in any other position to which the wheel can bedeflected.

Reference is made to FIGS. 14 and 15 which show schematic, partiallysectioned side views of a third embodiment of a caster in accordancewith the present invention. The third embodiment of FIGS. 14 and 15 isof substantially the same configurations as the second embodiment ofFIGS. 8 to 13 and differs principally in the configuration of the flexelement 74 and the location of the spring 66.

In FIGS. 14 and 15, the spring 66 has its upper end engaging the supportmember 14 coaxially about the swivel axis 16 and has its lower endengaging a circular boss 114 carried on the lever mechanism 30. In thecompressed position shown in FIG. 15, the lower end of the spring 66 andthe boss 114 are substantially coaxially with the swivel axis 16. Indeflection of the resilient bridge 76 from the unloaded position of FIG.14 to the compressed position of FIG. 15, the boss 114 is moved frombeing angled out of axial alignment with swivel axis 16 into becomingapproximately normal the swivel axis 116 and coaxial therewith.

Bridge 76 is shown in FIGS. 14 and 15 as formed with a single curvedportion as can be of assistance in controlling the deflection of thebridge 76.

The preferred embodiments shown such as in FIGS. 8 to 13 includes amounting member 12 to which the support member 14 is secured forswiveling about a swivel axis 16. Elements of the swivel coupling areformed directly into the central support panel 86. In accordance withthis invention, it is not necessary that the mounting member 12 beprovided. The invention may be utilized without swiveling as by mountingthe support member 14 directly and fixedly to an article. Such a wheelsupport assembly without the swivel mounting member is useful fornon-swiveling casters.

The preferred second and third embodiments of FIGS. 8 and 14 show, ineffect, two biasing devices which urge the support member 12 and thelever mechanism away from each other. These include firstly, the spring66 and, secondly, the resilient bridge 76. The spring 66 is notnecessary and the inherent resiliency of the flex element 74 and, inparticular, of the bridge 76 may be used alone to provide fordeflection. Of course, depending on the loading and deflectioncharacteristics desired, the relative spring strength and resiliency ofthe flex element 24 and its bridge 76 can be appropriately designed andselected.

FIG. 11 shows the resilient bridge 76 in side cross-section as having aU-shape with a straight middle portion which merges into two curvedportions. FIG. 14 shows the bridge as having a U-shape with a singlecurved portion. The nature of the bridge 76 is to be appreciated asaffecting its resiliency and the manner in which it deflects.

A person skilled in the art can alter the deflection characteristicsmany ways, for example, by changing the radius of the curved portionsand by substituting for the straight middle portion a convexly orconcavely or complexly curved member. Additionally, the bridge 76 couldhave stiffening embosses formed therein at various locations to changedeflection. For example, as a stiffening emboss, a rib could be formedin the bridge 76 which extends parallel a longitudinal axis 120 of theblank as indicated in FIG. 13 about which the blank is symmetrical. Suchribs could be provided, for example, only over the curved portion of thebridge 76 or one of the curved portions.

The embodiments of FIG. 8 and 14 show the flex element 74 as stampedfrom a single piece of metal. Rather than comprise a single piece ofmetal, the bridge 76 could be provided as a separate piece of resilientmaterial such as a length of spring steel which can be secured as byrivets at one end to the support member 14 and at its other end to thelever mechanism 30. After assembly, the flex element 74 would be aunitary element. Alternatively, a flat piece of sheet metal could beprovided to overlie the bridge 76 of the unitary piece of metal in FIG.13 and be secured to the support member 14 at one end and the levermechanism 30 as by rivets so as to provide a secondary spring as a leafspring to become tensioned when the bridge 76 is bent to its U-shape.

It is not essential, but rather preferred, that the embodiments of FIGS.8 and 14 have an indicator mechanism to indicate the extent of loading.Various indicator mechanisms may be provided other than the use of thelimit pins 104 also as an indicator.

The embodiment of FIGS. 8 to 13 preferably has at least limit pin 104,however, such a mechanism to limit either expansion or compression isnot necessary. The bridge 76 can itself provide adequate resistance toexpansion beyond a maximum expansion which would permit the spring 66from becoming disengaged from between the bosses. Maximum compressioncould be limited merely by the lever legs engaging the central leverpanel 92 or by other tabs, shoulders or the like being provided on thelever arms and/or support legs to interact between the lever arms 32 andthe support legs 26.

The embodiments of FIGS. 8 and 14 preferably have the unitary flexelement 74 formed from a sheet of metal as shown. The flex element maybe formed from other materials and/or composites as, for example,laminates of various materials. The flex element 74 can be formed fromplastic or nylon material. For example, a flex element 74 in a similarthree-dimensional form to that shown in FIG. 8 could be injection moldedfrom plastic as one piece. A flex element 74 made by injection moldingcould have varying shape, thickness, reinforcing ribs and the like toprovide desired strength and flexibility having regard to theapplication intended for the resultant caster.

Preferred casters as seen in FIGS. 8 and 14 may be made adaptable toreceive light loading in the range of 0 to 50 pounds or much greaterloads up to thousands of pounds of loads and greater.

Preferred casters use a steel sheet for flex element 74, however, othermetals such as aluminum could be used either in sheet form or possiblyas a cast part.

While the embodiment of FIGS. 8 and 14 show legs 26 inside of lever arms32, this is not necessary. Legs 26 could be outside of lever arms 32. Itis preferred that the legs 26 interact with the lever arms 32 and assistin keeping the central support panel 86 and the central lever panel 92in alignment as during deflection and/or to assist in taking any lateralloading. It is to be appreciated that other mechanisms could be providedand the legs 26 and lever arms 32 reduced and/or eliminated.

The three embodiments show wheel 36 journalled on wheel axle 37. Thewheel axle 37 is fixed against movement relative the lever mechanism. Itis to be appreciated that a known floating axle arrangement may besubstituted. With a floating axle arrangement, a spring biased mechanismis provided between the lever mechanism 30 and the fixed axle 37 whichpermits spring biased movement normal the axle depending on loadsapplied to the caster.

The present invention has been described with reference to preferredembodiments. Many modifications and variations will now occur to thoseskilled in this art. For a definition of the invention, reference ismade to the following claims.

We claim:
 1. A caster assembly comprising a mounting member mountable toan article, a support member having a central cup portion and two legsextending therefrom, the central cup portion mounted to the mountingmember for swiveling about a support axis, the two leg members extendingfrom opposite sides of the central cup portion away from the mountingmember generally parallel to each other spaced from each otherstraddling the support axis, an elongate lever pivotably coupled to thesupport member for pivoting of the lever relative the support memberabout a pivot axis generally normal to the support axis, the leverhaving two elongate arms extending generally parallel to each otherspaced from each other straddling the support axis and parallel to thelegs of the support, each of the two legs of the support member beinglocated adjacent a respective one of the arms of the lever with bothlegs either laterally inward of their respective arms or laterallyoutward of their respective arms a wheel rotatably mounted to the leverdisposed between the arms of the lever and between the legs of thesupport member, the wheel journalled on a wheel axle extending betweenthe arms for rotation about a wheel axis spaced from the pivot axis andparallel to the pivot axis, a spring member disposed between the leverand the support member biasing the lever to pivot relative the supportmember about the pivot axis in a clockwise direction to an unloadedconfiguration and that such to pivot the lever relative the supportmember about the pivot axis in an opposite, counterclockwise directionrequires deflection of the spring member with the spring memberrequiring increasing forces for deflection of the spring as the lever ispivoted further in the counterclockwise direction, a support indicatorcarried by a leg of the support member spaced from the pivot axisradially relative the pivot axis, a lever indicator carried by an arm ofthe lever spaced from the pivot axis radially relative the pivot axis, afirst of the support indicator and lever indicator comprising a scalehaving a plurality of markings each indicating a different extent ofdeflection, the support indicator and lever indicator disposed on theirrespective arm and leg in juxtapositioned complementary relation to moverelative each other in a first linear direction only on pivoting of thelever relative the support member about the pivot axis in the clockwisedirection and to move relative each other in a second linear directiononly on pivoting of the lever relative the support member about thepivot axis in the counterclockwise direction, wherein the positionrelative the scale of the one of the support indicator and leverindicator which does not comprise the scale provides a visual indicationof the extent of deflection of the spring member.
 2. A caster assemblyas claimed in claim 1 wherein the lever has a first end and a secondend, the pivot axis located intermediate the first end and the secondend, the wheel axis located on the lever proximate the first end, andthe spring member coupled to the lever proximate the second end.
 3. Acaster assembly as claimed in claim 1 wherein the lever extends from asupported end of the lever where the lever is coupled to the supportmember to a remote distal end of the lever on which the wheel ismounted, the lever proximate the supported end comprising a resilientsection adapted to resiliently deflect to provide for pivoting of thelever relative the support member about the pivot axis.
 4. A casterassembly as claimed in claim 3 wherein the wheel axis is located on thelever proximate the remote distal end.
 5. A caster assembly as claimedin claim 1 wherein the lever is pivotably coupled to the support memberfor pivoting of the lever relative the support member about the pivotaxis via a journalled coupling coaxially about the pivot axis.
 6. Acaster assembly as claimed in claim 1 wherein the lever has a first endand a second end, the pivot axis located intermediate the first end andthe second end, the wheel axis located on the lever proximate the firstend, and the spring coupled to the lever proximate the second end.
 7. Acaster assembly as claimed in claim 1 wherein the lever extends from asupported end of the lever where the lever is coupled to the mountingmember to a remote distal end of the lever on which the wheel ismounted, the lever proximate the supported end comprising a resilientsection adapted to resiliently deflect to provide for pivoting of thelever relative the mounting member about the pivot axis.
 8. A casterassembly as claimed in claim 7 wherein the wheel axis is located on thelever proximate the remote distal end.
 9. A caster assembly as claimedin claim 1 wherein the lever is pivotally coupled to the support memberfor pivoting of the lever relative the support member about the pivotaxis via an axle member coaxial with the pivot axis.
 10. A casterassembly as claimed in claim 1 wherein the lever is pivotably coupled tothe support member for pivoting of the lever relative the support memberabout the pivot axis via a journalled coupling coaxially about the pivotaxis.
 11. A caster as claimed in claim 1 including a maximum stopmechanism to limit pivoting of the lever relative the support member inthe counterclockwise direction to a desired maximum.
 12. A caster asclaimed in claim 1 including a stop mechanism to prevent pivoting of thelever relative the support member except between a retracted positionand an extended position.
 13. A caster as claimed in claim 1 wherein thelever indicator and support indicator are carried on the caster assemblyto permit visual inspection to indicate the extent of deflection of thespring member.
 14. A caster as claimed in claim 1 wherein the scalerepresents a quantitative indication of loading transferred via thecaster assembly onto the wheel.